Coaxial switch



Feb. 17, 1948a T. A. NEWKIRK COAXIAL SWITCH Filed Aug. 4, 1944 INVENTGR. THO MAS ANEWKIR'K BY//Akw,

Patented` Feb. 17, 1948 UNITED STATES PATENTv OFFICE COAXIAL SWITCH Thomas A. Newkirk, Fairfield, Ohio Application Alltult 4, 1944, Serial No. 548,122

4 Claims. (Cl. 200-6) (Granted under the act of March 3, 1883, as amended April 30, 1928: 370 0. G. 757) The invention described herein may be manu factored and used by or for the Government for governmental purposes, without the payment to nie of any royalty thereon.

The invention to be hereinafter described reiates to multiple contact rotary switches for ccaxial lines in radio circuits.

it is particularly applicable to radio circuits.

Where a radio circuit conductor is bent or deflected at a sharp angle as is often the case in switching iromone part to another of a. line or from one line to another line, the resulting reflec- 'tion is a serious objection. n coaxial lines in radio circuits any bending or deflection is conducive to variation inthe surge impedance, as is well known. That is due to theI fact that the radial distance between the conductors, 'in the area of the bend or deflection generally varies. Such variation in surge impedance is a further serious objection in many ofthe existing switches. .fl further difficulty with many existing types of `multiple contact rotary switches for coaxial lines is that the selected contacts, at any one time or position are. not adequately isolated from those not so selected, with resulting uncertainty of and inefficiency in operation.

The main objects of the present invention are to overcome the above and other diilicultles and deficiencies'and provide a simple, compact, elli cient and relatively low cost rotarymultiple contact switch, which will selectively make any one of a :number of connections, at an angle, between one line and any other given line of a predetermined group or series of lines, minimizing reilection effects and'variation in surge impedance and, at the same-time, adequately isolating all contacts except vthose specifically selected.

In order to more clearly disclose the construe tion, operation and use of the invention reference should be yhad to the accompanying drawings forming part of-the present application.

Throughout the `several figures of the drawings like'reference characters designate the saine parts In the drawingsg Fig. 1 is a top plan view;

Fig. 2 is a. top plan view with cover plate re- Hg. 6 is a fragmentary cross section, enlarged, showing the plunger 22 in side elevation.

While the terms inlet and outlet or input and output are relative to the direction of flow and the direction of flow is not iixed or permanent but may be varied with circumstances, it will be simpler and more convenient to designate the directions of now in the present application and refer to inlet and outlet relative thereto. Actually they are end or terminal connections, whether inlet end or outlet end.

The casing i is, preferably, cylindrical and of brass or other suitable material. Brass is readily machined. It could be of other readily mold able material.

l't is provided with a sleeve? of standard type to receive the usual electrical connection, the sleeve being mounted centrally in the base ci the cylinder. A plurality of standard similar inlet or input connectors 3 are disposed at intervals in the cylinder side wall. For purposes hereinafter disclosed, these input connectors are cilsposcd in'the same circumferential plane in the cylinder wall.

Within the cylinder is revolubly mounted a split block comprising two complementary halves, the matching or cooperating faces being provided with certain bores, channels, grooves, etc., as will hereinafter appear. The split block, as a whole and in assembled relation is rectangular having one dimension corresponding to the inside depth or vertical measurement of casing i and a second dimension corresponding to the diameter of casing i. When positioned, the ends of block 4 will be in free running or sliding contact with the inner wall of casing I except as will be hereinafter set forth. To give a smoother running flt and continuous bearing between the cylinder wall and the whole adjacent block end, said ends are rounded on the same radius or curvature as that of casing i. To effect rotation of block 4 a shaft 5 is provided midway of its length, extending laterally of it, and, in assembled position, coincident with the vertical axis or center of casing i. A simple way to secure this shaft in the block is to provide the two halves with matching shaft grooves 6. When the block halves are secured together by screws 1 or the like they securely clamp shaft 5 so that the block must rotate with the shaft. For easy operation shaft 5 may be provided with a knob or other handle 8. A posi tive connection may also be provided by a setscrew passed through the block and turned in against the shaft, in well known manner.

' 55 In order to yieldingly maintain the block in respective selected positions. a small plunger 8 with rounded or inclined operative end is provided. This plunger is mounted in a bore formed by matching grooves Il! in the block halves and is mid-way between the sides of the block. It is urged to operative positions by a compression spring il conned between it and the inner end of the bore or assembled grooves. Plunger 9 cooperates with sockets, seats or notches it in the cover plate i3.

Centrally seated in block 4 and projecting therefrom is a standard outlet or output connec tion i4. The outlet connection is also so placed as to constitute the axis of rotation for block i and ,is'journaled in the sleeve 2, when the parts are operatively assembled. The matching halves are provided with quadrant or quarter circle grooves, channels, etc., i5 of circular cross section. These grooves extend from the lower edge of the block at its axis oi.' rotation in assembled relation. to a point n ear its upper edge terminating in its vertical wall or end. In the upper end and extended at right angles to connector iii is slidably mounted a cylindrical plug or contact i8 having its outer end wall ground to the same arc or curvature as that of the cylinder wail. To maintain I6 in sliding contact with cylinder i a coil spring I'I-may be used.

Concentrically within the assembled grooves i5 is a central conductor I B of copper or the like and either tubular or solid, as the case may be, Its ends are seated in insulating sleeves le. which. in turn, extend into the connector I4 and plug I8. It has been found that the conductor I8 usually. is sufficiently self-sustaining to maintain its curvature and concentric position, after it has once been shaped. In cases where it seems advisable to rely on other means, suitable insulating spacers may be provided at intervals. The block d and particularly theconcentric groove wall I5, constitutes the outer conductor of the coaxial circuit. For that purpose, the plug i6, in sliding contact with the block, by spring pressure, is also in sliding contact `with the cylinder wall. As the block is rotated, plug I8 will engage the inner wall ot the respective input connectors t, successively establishing electrical connection at each. At the same time, a small radially directed spring pressed plunger 22 in the outer end of center conductor I8 will similarly contact with the center conductor 0f the respective input connec tor 3, completing that connection. By having plug I 6 and plunger 22 sli'dably mounted and constantly maintained in wiping contact with cylinder wall. all wear will be automatically taken up and reliable wiping contact will be continuously maintained. A small pin and notch maintain II against rotating in its socket so that its outer curved surface will remain in proper free sliding contact.

do At no point in its length does it assume any ecceni 4 as the block is rotated. all others being completely isolated.

Since plunger t and notches i2 cooperate. the notches are so distributed that they may be aligned with respective planes passing diametriG cally through casing i. and, therefore, through the respective axis of one or another of the input connectors 8. So, in assembling, the cover plate i8 is connected to casing Il with the respective notches i2 properly positioned relatively to the connectors ii. Then rotations of bloch l by shaft Ei will successively complete the circuit through the centrally disposed outlet and the respective inlet 8. As the circuit is completed, plunger $3 will drop into the corresponding notch i2,`spring ii yieldingly maintaining it against accidental 'gtgtion ci block l such as would break. the conc As a matter of convenience in dete "f 'i'. ff. the exact circuit being completed, each input connection may be numbered. Conveniently this number may be placed on the cover plate, where it will be readily seen. A dial plate 2i may be connected, concentrically, to shaft 5 to rotate therewith and provided with an opening 2i' placed to fall over the respective numbers as vthe shaft is rotated so that as block d moves to various con tact positions the corresponding circuit or cable number will appear through the dial. 0f course, a pointer or other device may be similarly used.

It will be noticed that there is no sharp angle in the connection but a gradual, steady and regu lar curve thereby minimizing to a very great ex tent all objectionable redaction eiects regularly encountered where the connections do include angular changes in direction.

Also, as clearly shown, the central conductor is maintained concentric throughout its length in block d, relative to the outer coaxial conductor.

tricity relative to the outer coaxial conductor. This, as previously indicated, greatly minimizes variation in surge impedance.

The two complementary block halves or sec- 5 tions may be separably connected in any suitable Bo and use or the invention will be clear from the preceding detailed description.

f Changes may be made in the construction, arrangement and disposition of the various parts of the invention within the scope of the appended 55 claims without departing from the field of the It will be noticed that the entire inner cylindrical wall oi casing I is thoroughly electrically insulated as at 20 except at the inputs 3 which extend through the insulations in the path of rotations of the block and its plug.

'I'he end oi' the block opposite plug I6, is notched as at 23 to provide ample clearance between that end and an input connector while connection is established through the dlametrically opposite input connector, as above. This avoids chance of short circuit, as will be clear.

kIn view of the above description. it will be seen that there can be no short circuiting between the block and cylinder wall and that only one input invention, and it is meant to include all such within this application wherein only one preferred form has been illustrated, purely by way oi example and with no thought of, in any degree,

j@ limiting this invention thereby.

Having thus described my invention, what I claim and desire to protect by Letters Patent is: l. A multiple contact rotary switch of the character described comprising a cylinder pro- YIl vided with an axially disposed opening through 10 right angles tothe aforesaid axially disposed opening in a plane parallel to the cylinder axis. a block rotatably mounted within said cylinder and extending diametrically across the kinterior or said cylinder, said block comprising a pair of at any one time can be brought into the circuit, il complementary pistes each having a quarter- 

